William j



tntrd tatrt WILLIAM J. COCHRAN, oF BALTIMORE, MARYLAND.

Letters Patent No. 90,819, dated June 1, 1869.

IMPROVEMENT IN TH CONSTRUCTION OF RETORTS FOR THE MANUFACTURE OP COAL-GAS.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom 'it 'ma/y concern.'-

Be it known that I, WILLIAM J. COCHRAN, of the city and county of Baltimore, and State of Maryland, have invented a new and useful Improvement in the Construction of Betorts for the Manufacture of Coal- Gas, and for other purposes; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawing,

making part of this specification.

The nature of my invention consists in making a retort of iron and lire-clay, in combination, the iron forming a lining or foundation-frame for the retort, and the` tire-clay the exterior covering, or principal component thereof.

To enable others skilled in the art to make and use my invention, I will proceed to describe the manner of constructing the same.

I make my retortof any required size or shape, the accompanying drawing representing a transverse section of the form of retolt usually adopted in the manufacture of coal-gas, the interior portion, B B, of which is a thin cast-iron shell, or lining, having upon its outer surface numerous spines, or prickers, c c c, for

the purpose of holding or securing thereto the outer covering of refclay A A.

The inner casting or liuing,-B B, being thus prepared, is covered with the fire-clay, in a plastic condition, to the proper thickness and shape, during which operation the casting B B should be mounted on bearings at its ends, in any convenient manner, to admit of rotation upon its axis, so as to facilitate the covering and moulding-process. The retort is then dried and burnt, or tired in the ordinary way.

'lhe tempering of the Clay and the treatment of the retort, after claying, is substantially the same asin the manufacturing of fire-brick retorts. .n

Formerly retorts for the production of coal-gas were exclusively made of cast-iron; but the long-continued action of the great heat to which they are necessarily exposed while in operation rapidly destroys the integrity of the iron, and causes it to crack into numerous fissures, more or less open, through which the gas escapes from the retort into the fire-chamber, and is wasted.

The wastage in this manner, even from small fissures, soon amounts to more than the original cost of the retort.

An iron retort seldom remains perfect for more than two mont-hs, but they are generally allowed tol remain in use for three months, or longer, before being renewed, notwithstanding the great wastage of gas thus lire, a saving in firstgcost was thereby eiected', as such retorts may be continued in use for ltwo years and npwards, although not in a perfect condition, for when removed from the bench they are generally in a dilapidated condition, having Inore the appearance of a 'dry wall of rubble-stone than the smooth continuous surface of a tight and serviceable retort, thus indicating a great wastage ofthe gas.

Fire-brick, however, is at best a porous substance, and the hydrogen and other subtile elements of the gas readily pass through it. And it is well known that new brick retorts will waste the gas by its permeating through their substance; but it is alleged that in time the` grosser particles of the gas lodge in the pores, and thus stop the wastage.

The cost of this wastage, however, is said to be equal to twice the cost of the new retort before it is thus stopped, and by the -time the retort is made impervious deterioration commences, in the form of cracks and fissures, the wastagefrom which goes on increasingly, until the retort becomes unfit for use.

The wastage from fire-brick retorts from these causes, notwithstanding their apparent superior durability, is so great, when compared with the wastage and expense of iron retorts, that many intelligent and careful gas-engineers continue the use of iron' 'retortsn the establishments controlled by them, as the more economical of the two.

My improved retort, combining the impermeable properties of the iron with the refractory properties of the fire-brick, the greatest-,possible economic result is thereby produced, for it is obvious that there.' is no wastage from such retort while new, and as the iron lining secures the proper'form and integrity of the retort, so long as it is protected, by the tire-brick covering, from the action of the external heat, no Wastage can take place while this condition isA mauitained.l

ture of such purposes may require; thus, the lining B B may be made with holes through it, as shown at el d l d, into which holes the covering of fire-clay may enter, as shown in the drawing, and in some cases, or for some purposes, these holes may be made so large, and .the iron between the holes so small, that the iron part will more resemble a skeleton of thev retort han an interior lining; and in such case also the reiclay may be caused to spread over the ,interior of the retort, so as to completely imbed such iron former or skeleton within the walls of the retort, in which cases,

also, if preferred, the spines or prickers c c c c may be dispensed with;

I do not confine myself to any particular form of the retort, nor toY any particular mode of combining the iron and the clay together, but claim the right,

under this patent, to vary the construction so as to obtain the best result, in view ofthe purpose to which the required retort is to be applied.

` Having thus described the nature and construction of my improvements in retorts for the production of coal-gas or other purposes,

What I claim therein as my own invention, and desire to secure by Letters Patent of the United States, is-

A retort for the production of coal-gas, or for other purposes, composed of iron and fire-brick, or fire-clay, in combination with each other, in the manner and by the means substantially as herein described.

WM. J. COCHRAN'.- Witnesses JAS. H. KERNAN, K JNO. E. COCHRAN. 

